The use of conventional independent hazardous condition (e.g., carbon monoxide gas "CO" or combustion gases or particles, commonly known as "smoke") detectors throughout a dwelling structure is promoted as an accepted and desirable safety feature that facilitates an effective warning for the occupants of the structure. CO and smoke detector devices are readily available in most hardware and department stores at fairly reasonable cost. They are simple to install in various rooms of a dwelling. Although some units require connection to the electrical system of a dwelling for power, other units carry their own independent battery power sources. These detectors have become very popular and are commonly used. Each such detector monitors a condition, such as the ambient air in the case of CO or smoke detectors, in its respective local area and only the individual detector that senses a hazardous condition generates an alarm, a local alarm indication. Whenever one unit is activated other detectors in remote locations of the dwelling are not affected. An activated detector can warn the occupants of a dwelling within hearing distance of the activated detector when the alarm is audible, and within sighting distance when the alarm is a flashing light. While safety officials have continued to promote the use of these inexpensive independently powered units and encourage their use in every room in a dwelling structure, there is one important shortcoming of this type of alarm system: communication.
The problem with conventional independent hazardous condition detectors is that a detection of smoke or CO in one room of a house is not necessarily communicated to all the occupants of the dwelling at the very time it should be communicated. For instance, an audible alarm generated by an activated independent smoke detector located in a basement furnace room of a house may not be heard by occupants in second or third floor bedrooms. This is especially so at night where people sleep in bedrooms with closed doors. Even if other detectors are located in the various bedrooms and at the head of each stairway leading to those bedrooms, there is no contemporaneous warning communicated to the occupants. Only later, when the smoke seeps through the house in sufficient concentration is it sensed by one of those other detectors near the bedrooms and warning is given that alerts the nearby occupants. By this time, the dwelling may be so consumed in smoke or flames that the later alarm may not provide sufficient time for the occupants to escape safely.
Similarly, an alarm provided by an activated detector in a closed bedroom may not be heard or otherwise detected by occupants in other rooms soon enough to rescue those in the bedroom containing the activated detector.
Integrated systems for fire and smoke detection are known, in which several remote sensors are wire connected to a central control station within the dwelling. The central control station controls the activation of one or more distributed alarm devices when a hazardous condition is detected at any sensor location. That type of system can be configured to activate any or all alarm devices within its control and is therefore more desirable than the aforementioned system made up of conventional independent detectors. However, an integrated system requires extensive wiring to interconnect the control station to the various sensors and alarm devices located at various locations throughout the dwelling structure. An integrated system is usually installed during construction of a dwelling structure, in order to conceal the wires within the walls. If a building is retrofitted for such a system, the choice is to leave the wires exposed or proceed with the highly labor intensive process of routing the wires through existing walls and floors. In any event, the cost of the components utilized and the skilled labor involved to install such an integrated system is known to be relatively expensive and therefore not readily affordable by most consumers. In addition, an integrated system can only be expanded for additional coverage by running more wires to each newly monitored or alarmed locations.